The present invention relates generally to electrical energy supply and distribution, and more particularly, to a power load leveling system including energy packet storage components. Electrical energy generation and distribution has been a mainstay for residential and commercial energy needs for societies all over the world for many years. Various forms of electrical energy generation have existed for some time now, including coal fired power plants, nuclear power plants, hydro-electric plants, wind harness plants, and others. All of these forms of electrical energy generation are well known to those of skill in the art of power generation and details of their operation need not be set forth herein. Many volumes of published literature exist on all of these well known forms of electrical power generation, from sources all over the world.
As power generation has advanced power usage has increased. This is due to many societal factors. First, populations in practically every country of the world have increased, resulting in more power needs. Second, consumer products frequently are designed to use electrical energy in order to operate. Due to advances in technology, more electronic products are available for use today than at any time in world history. Third, manufacturing plants have realized that machine automation can increase plant productivity and decrease production costs. Such automation usually requires electrical energy. Thus, the overall result is a greater need for electrical energy than ever before.
Another common occurrence around the world related to energy consumption, is that consumption is greater during certain hours of the day. In any given time zone, electrical energy usage is greatest during the hours of 6 AM and 10 PM, commonly referred to as the xe2x80x9cawake hoursxe2x80x9d or waking hours. Between 10 PM and 6 AM the next day most people are sleeping and, therefore, using less electrical energy. These hours are commonly called the xe2x80x9csleeping hoursxe2x80x9d. In order to avoid energy xe2x80x9cbrownoutsxe2x80x9d, or worse yet xe2x80x9cblackoutsxe2x80x9d, power companies have to be able to meet xe2x80x9cpeak demandxe2x80x9d requirements of any given 24 hour day. These peak demand requirements occur during the awake hours and historical data obtained from tracking energy usage can fairly accurately predict how much energy will be needed each hour of each day in practically any community. Therefore, peak demand is one of the main drivers of the size and number of power plants needed for any given area.
The problem with using peak demand requirements to determine power plant capacity, is that it does not make for efficient use of the resulting power plant. For example, if a peak demand period in a given area is X kilowatt-hours and that demand is only required for a period of eight hours each day, and the average demand for the rest of the day is half of X, then the design capacity of that power plant for the other sixteen hours of each day is not being effectively utilized. Said another way, if the full energy production capacity of each power plant, for each day, was utilized, less power plants would be needed because each one would be fully utilized, all day, every day. Design and usage could then be based on total energy needs each day rather than peak demand needs. Using peak demand requirements also results in an inefficient use of the distribution and transmission systems used by the power plants to deliver the electrical energy they produce.
The present invention enables power load leveling throughout each day. Load leveling is the balancing of energy production at a power plant so that the plant is generating about the same amount of energy for all hours of operation, while supplying its customers with their full energy needs throughout the day. Since peak demand periods will likely continue to exist, load leveling may be accomplished by the use of energy storage devices. In other words, by producing energy and storing that energy during low demand periods, such as during sleeping hours, the stored energy can be used during peak demand periods to offset the amount of energy that must be produced during the peak demand periods.
In accordance with one embodiment of the present invention, energy production is made more level throughout each day. At night, for example, energy is produced and stored in specialized capacitors, which may be located at or near a power plant or a power substation, for example. The next day the stored energy may be injected into a utility""s power distribution and transmission grid to supply all or part of the energy needs in, for example, a given home, business, or area that is connected thereto. By using the stored energy during peak demand periods, less energy is needed in real time production from the power plant servicing that area. In other embodiments of the present invention, the capacitors may be constructed to be placed in a home, such as in a basement or nearby out building. Larger capacitor-based energy storage systems may be placed in or near a business office or factory. Conversely, it is also possible to produce such systems on a smaller scale for installation at individual loads, such as, for example, in copy machines, PC""s, servers, or a multitude of other equipment that requires a supply of electrical energy to operate. Preferably, whether the capacitor-based energy storage systems are placed near the end user of the system or at a power production or distribution location, the systems are of modular construction to allow for efficient set-up, expansion, and repair. Modularity is preferably maintained at both the source and load side of each system. In any of these embodiments, the present invention enables stored electrical energy to be used during peak demand periods to lessen the reliance on real time, direct electrical energy supplied and distributed by a power plant.
The present invention may be accomplished by conventional energy distribution equipment being connected to capacitors of high energy storage capability, wherein the capacitors may be xe2x80x9cchargedxe2x80x9d with energy produced at a power plant as often as desired. The power plant that supplies the charging energy to the capacitors may be a conventional fossil-fuel burning or nuclear power plant, or may consist of an alternate power source, such as, for example, a solar, wind, or hydroelectric source. Unlike known energy storage systems, such as battery storage systems, the capacitors of the present invention allow for the direct storage of large amounts of electrical energy. Capacitors are electrostatic devices that can store and transfer electrical energy directly and, as such, do not require the transpiration of a chemical reaction in order to generate electrical energy, as do batteries. Additional conventional electrical equipment may be used to connect the capacitor(s) to the home, business, or area being serviced, and to transfer the electrical energy from the charged capacitor(s) to an end use. The electrical energy supplied by the capacitors may be delivered in DC form, or may be delivered as single-phase or multi-phase AC. Converter/inverter equipment is preferably provided to properly alter the form of the electrical energy provided to, and drawn from, the capacitors.
In the present invention, specialized capacitors are used to facilitate the above-described system. In one embodiment of the present invention, the capacitor may be of the electrochemical variety, and either symmetrical or asymmetrical in design. The electrochemical capacitor enables significant, direct electrical energy storage in heretofore unmatched, small unit sizes. Other embodiments of the present invention may employ, for example, electrolytic, or cryogenic capacitors that can also provide the desired energy storage.
An inherent benefit of the present invention is the ability to substantially reduce or even eliminate anomalies such as power xe2x80x9csurgesxe2x80x9d, xe2x80x9cspikesxe2x80x9d, and xe2x80x9cskipsxe2x80x9d, thereby improving what is generally referred to as xe2x80x9cpower qualityxe2x80x9d. These phenomena are the unfortunate, and practically unavoidable result of moving electrical energy (i.e., electrons) over miles of distribution and transmission lines to end users. Power quality problems can occur for a number of reasons including, for example, electrical system design errors, electrical system construction errors, grounding errors, harmonics and load interactions. While these anomalies are not very common when one considers the total amount of energy delivered each day to any area, they nevertheless can result in significant problems for end users. For example, in this age of computer usage, an energy spike or skip, however brief, can cause electronic documents to be lost, or worse yet, can cause computer system damage. In contrast to the concept of electrical energy storage described above, the electrical energy that must be provided for maintaining power quality is extremely brief in duration. For example, it has been found that most power quality phenomenon occurs within 1 AC cycle or less, and that 10 cycles is usually more than sufficient to relax any momentary disturbance in the supply voltage. Thus, for purposes of the present application, power quality maintenance or improvement is generally defined to mean the ability of the present invention to provide a required level of power output for 1 second or less. When used for power quality purposes, the electrical energy stored in the capacitor(s) is preferably not depleted. This function is converse to the electrical energy storage function, wherein the energy storage system of the present invention may be operated to provide substantially more long-term power to a load or loads, and wherein the capacitor(s) may be discharged until the energy reserves thereof are substantially depleted or until manually shut off. Thus, although electrical energy storage and power quality maintenance are distinguishable tasks, the system of the present invention can operate to effectuate both. For example, one embodiment of the present invention provides an on-site capacitor(s) to directly service the energy needs of that site using stored energy instead of real-time, direct supply energy. The use of the stored energy from the capacitor(s) may be used not only to supply the power requirements of loads at the site, but may also be used to ensure power quality through the short duration discharge of electrical energy in response to power quality disturbances. Similarly, an off-site system according to the present invention may be used to achieve the same effect. Consequently, it should be realized by one skilled in the art that the system of the present invention may typically be collaterally utilized to maintain and improve power quality.